Project description

deprecation

The deprecation library provides a deprecated decorator and a
fail_if_not_removed decorator for your tests. Together, the two
enable the automation of several things:

The docstring of a deprecated method gets the deprecation details
appended to the end of it. If you generate your API docs direct
from your source, you don’t need to worry about writing your own
notification. You also don’t need to worry about forgetting to
write it. It’s done for you.

Rather than having code live on forever because you only deprecated
it but never actually moved on from it, you can have your tests
tell you when it’s time to remove the code. The @deprecated
decorator can be told when it’s time to entirely remove the code,
which causes @fail_if_not_removed to raise an AssertionError,
causing either your unittest or py.test tests to fail.

Usage

…but doesn’t Python ignore DeprecationWarning?

Yes, by default since 2.7—and for good reason [1] —and this works fine
with that.

It often makes sense for you to run your tests with a -W flag or
the PYTHONWARNINGS environment variable so you catch warnings
in development and handle them appropriately. The warnings raised by
this library show up there, as they’re subclasses of the built-in
DeprecationWarning. See the Command Line
and Environment Variable
documentation for more details.

Even if you don’t enable those things, the behavior of this library
remains the same. The docstrings will still be updated and the tests
will still fail when they need to. You’ll get the benefits regardless
of what Python cares about DeprecationWarning.

Exposing application users to DeprecationWarnings that are
emitted by lower-level code needlessly involves end-users in
“how things are done.” It often leads to users raising issues
about warnings they’re presented, which on one hand is done
rightfully so, as it’s been presented to them as some sort of
issue to resolve. However, at the same time, the warning could
be well known and planned for. From either side, loud
DeprecationWarnings can be seen as noise that isn’t
necessary outside of development.